Flexible wood floor tiles



May 27, 1958 A. ELMENDanF `2,835,936

FLEXIBLE WOOD FLOOR TILES Filed Oct. 29. 1953 United States Patent O FLEXIBLE WOOD FLOOR TILES Armin Elmendorf, Winnetka, Ill.

Application October 29, 1953, Serial No. 38%,116

Claims. (Cl. 20-75) The present invention relates to floor tiles composed of hardwood Veneer, such as oak, bonded to a flexible backing and adapted to be laid with an adhesive on conventional sub-floors such as concrete. Since the veneer generally ranges in thickness from .1 to .2 a floor covering composed o-f such tiles is much less expensive than conventional wood flooring that ranges in thickness from 1/2 to 1%6. The use of such veneer tiles brings into being problems conventional wood flooring does not present, some of which arise from the fact that a period of high atmospheric humidity may introduce serious .swelling stresses in veneer, whereas it has no objectionable effect on a floor of conventional thickness.

Installation costs can also be kept low, provided that the tiles can be laid on the underlying floor as easily and effectively as in the case of flexible, plastic tiles. Here again unexpected difficulties have been encountered, resulting in unsatisfactory installations due, usually, to inadequate bonding to the sub-floor or to a combination of such inadequate bonding with inadequate provision for expansion of the wood in the tiles.

Unsatisfactory bonding has resulted in allowing the tiles to spring away from the sub-flooring, particularly at the corners of the tiles when the sub-flooring is not perfectly level. The separation from the bonding adhesive takes place while the adhesive is still soft and tacky, resulting in a slow yielding of the bond until complete separation frequently takes place over a substantial portion of the bonding area. Thereafter, expansion of the wood in high humidity weather sets up stresses that are not adequately constrained, with the result that the tiles will heave up and produce in the floor unsightly bulges that are diicult to correct.

Heretofore many thousand installations have been made of Wood iloor tile each composed of a layer of wood strips, or a layer of wood divided into strips spread apart and connected togetherby uncut strands crossing the gaps between the strips, have been made. Tiles have also been made by dividing a layer of wood into blocks separated by gaps running parallel to the wood grain and crossed by unbroken wood fibers and other gaps extending crosswise of the grain. However none of these previous expedients succeeded in overcoming the faults to which reference has been made. Even widening the gaps to provide more space for expansion has not helped but, in some cases may create more difficulties than it cures.

The object of the present invention is to solve the problem of creating a tile construction that shall remedy all of the aforesaid faults of prior one-layer Wood veneer floor tiles and, when laid, shall consistently insure a sound flooring of attractive appearance.

2,835,936 Patented May 27, 1958 The various features of novelty whereby the present invention is characterized will hereinafter be pointed out with particularity in the claims; but, for a full understanding of the invention and its objects and advantages, reference may be had to the following detailed descrip tion taken in connection with the accompanying drawing, wherein:

Figure 1 is a face view, on a small scale of one of my improved tiles;

Fig. 2 is a face view of the same tile, on a larger scale, showing only a fragment at one corner;

Fig. 3 is a section on line 3 3 in Fig. 2;

Fig. 4 is a section on line 4 4 in Fig. 2; and

Fig. 5 is an edge view, on a still larger scale, showing fragments of two meeting blocks, the broken lines indicating a closed gap.

Referring to the drawing, 1 represents a moistureresistant membrane bonded to the under side of and forming a backing for a layer 2 of hardwood, such as oak veneer; the wood grain being parallel to the plane of the backing. This composite member constitutes a Hoor tile which may be of any desired size and shape; the drawing illustrating a square tile. If a side of the tile illustrated is nine inches, each block 3 into which it is divided will be 11/2" wide and 3" long.

The backing must be fibrous and yet plastic in order that it be flexible and yield adequately without splitting. lf the backing is too thin it cannot yield effectively when subjected to shear stresses in the plane thereof upon expansion of the wood, and is apt to split. The thickness should therefore be at least .02 and, up to a thickness of .06, it will remain sufficiently pliable readily to conform to the surface irregularities of an uneven floor on which the tile may be laid.

Flexibility is given to the wood layer through its division into small blocks that may be entirely separate from each other; or, if they remain connected to each other it must be only by webs so thin as to allow the wood layer to bend at the webs. The wood layer therefore possesses the degree of limpness needed to enable the tile as a whole to lie snugly against an underlying floor; thereby avoiding the danger that it will lift at one or more points and pull away from the floor before such conventional adhesives as `emulsied asphalt, outback asphalts and those derived from reclaimed rubber, can take a set.

The blocks in each tile must be separated from each other by gaps 4 and 5. The critical gaps are gaps It, namely those that run parallel to the wood grain and provide the spaces into which the blocks expand. Gaps 5, on the other hand need only provide for flexibility of the veneer in one direction while harmon izing with the gaps of the other group in the matter of ornamental design.

The gaps must not be too wide or else the product will not be commercially acceptable. With rectangular blocks 11/2 wide, as shown the gaps may havewidths equal to 6% of the width of a block and still be commercially acceptable. It is not always necessary to have so great a gap width, but it should always be more than 2% of the width of a block.

The primary factor in determining the width of the gaps depends on the capacity of each particular kind of wood to expand upon an increase in its moisture; such expansion occurring in wood in its natural state whenever its moisture content increases at times when the latter is below the fiber saturation point. There are known processes to which wood may be subjected for the purpose of reducing its capacity to expand. Thus, when wood is dried while constrained against shrinking as it loses moisture, its capacity to expand upon subsequently taking up moisture is reduced by at least one half. A similar result is achieved by partially impregnating wood veneer with a synthetic resin of the phenolic and urea types. With such processed wood the gaps in some instances need not be much greater than 2% of the width of a block.

The illustrated tile may easily be made by sawing down through the top face of the veneer either before or after the backing has been applied. If the saw cuts extend clear through the veneer all direct connection between the blocks is severed, each block being held in place in the design only by the backing, although tie blocks retain the same positions relative to each other as they did in the original tree. This method of dividing the veneer also simplies the creation of thin webs 6 at the bottoms of the gaps, since only enough wood need be left at the bottoms of the gaps to insure that the backing is not exposed; the main purpose of these webs being to prevent bleeding of the saturents used in some types of satisfactory backing material, when varnish or similar types of floor finishes are applied to the wood.

l prefer to bevel the blocks at the top along all four of their edges, as at 7, thereby avoiding sharp corners that may splinter easily in use of the floor; and, in addition, making changes in the gaps proper less noticeable as the wood expands and contracts.

Laying of the tiles is simple and easy, the tiles being Yso limp that only light pressure is required to bring all parts of each tile into intimate contact with the su'ooor; the tiles remaining snugly in place, without further attention being paid to them, until the adhesive between them and the subtloor takes a set,

After a flooring has been laid, the individual wood blocks may expand and contract freely with changes in their moisture above the amount present in the wood when it is in the comparatively dry state existing at the time of laying the flooring. Because of the type of backing material used in the tiles, the expanding movements of the blocks is not impeded by the backing and, because of the thickness of the backing, the stresses imposed by the block movements are absorbed within the backing, without impairment of the bonds between the backing and the wood and between the backing and the sub-floor. Consequently the flooring remains unimpaired and solidly fastened to the sub-floor indenitely.

Upon a large increase in their moisture the blocks in each tile may completely close, leaving only V-grooves along the lines of gaps 4. Gaps will remain open but, looking at them from above, they do not differ greatly in appearance from the V-grooves which is all that is left of gaps 4.

Should the gaps close before the tendency of the wood to expand has been satisfied, the wood may compress a little at gaps 4 without harm to the iiooring.

it should be noted that the webs have so little mass that their effect on expansion of the blocks is negligible, the reaction of the blocks to expansion forces being substantially the same as though these webs were not present.

lt should further be noted that while only a single block arrangement, six parallel columns each containing hree rectangular blocks, aligned, lengthwise, has been shown, the invention is not limited to this particular design.

l claim:

l. A flexible floor tile consisting of a layer of wood, the capacity of which for expansion across the width thereof upon an increase of its moisture from a cornparatively dry state to a state of fiber saturation is about one half that of a similar piece of wood of the same species in its natural state, and a moisture resistant, flexible backing bonded to thc wood: the wood layer being from .1 to .2l thick and being separated throughout at least substantially its entire thickness into blocks by gaps extending down through the top face of the tile and arranged in two groups in each of which the gaps are parallel to each other and extend from an edge of the tile to the opposite, edge, one group being positioned crosswise of and the second group paralleling the general direction of the wood grain, the gaps in the second group, at their narrowest points, having a width while the Wood is in such comparatively dry state, slightly less than the maximum expansion of the blocks upon becoming saturated, in use, with moisture, and the backing having a thickness sufficient to allow the face of the wood in contact with one face of the backing to expand and contract without injury to the backing while the other face of the backing is constrained against contraction and expansion.

2. A flexible floor tile as set forth in claim l, wherein the gaps extend through the top of the wood layer to such a depth that only a thin web or membrane which offers only negligible resistance to the closing of the gaps remains at the extreme bottom of the gaps.

3. A flexible floor tile as set forth in claim l, wherein the blocks are about ll/z wide across the grain, the backing is of plastic, fibrous material from .02 to .06 thick, and the width of the gaps of the second group is from a little more than 2% and not more than V6% of the width of a block, at the narrowest portions of these gaps.

4. A flexible wood floor tile consisting of several parallel rows of several blocks each, bonded to a thick moisture-resistant brous membrane, the wood grain in the blocks being parallel to said membrane and running lengthwise of the rows, the blocks in each row being spaced apart end to end so that they are in exactly the same position relative to each other that the wood in the blocks occupied in the living tree, the several rows being spaced apart, the wood, the capacity of which to expand in width for a given increase in its moisture content is no more than half that of a similar piece of wood. of the same species in its natural uncompressed state, the gaps between the block ends being arranged in parallel lines, the width of the gapswhile the wood is comparatively dry, between the rows being greater than 2% and less than 6% of the block width, all Vof the gaps being open at the top face of the tile, and the moisture-resistant membrane having a thickness of about .02 to .06 and being plastic so that it does not fail in shear when the tile is bonded to a non-expanding base and the blocks expand to the point where the gaps between rows close.

5. A flexible wood floor tile as set forth in claim 4, wherein the gaps are all ot the same width and the four edges of each block, at the top surface, are beveled.

6. A flexible wood floor tile as set forth in claim 4, wherein the space between the blocks terminate in bevel edges at the top surfaces and the widths of the gaps in the plane of such surfaces is about the same for all gaps.

7. A flexible wood tile as set forth in claim 4, wherein the bottoms of the gaps are spanned by a thin mem brane of wood in contact with the backing.

8. A flexible wood floor tile as set forth in claim 4, whereinthe blocks are made of a single layer of wood veneer from .1 to .2 thick.

9. A flexible wood floor tile as set forth in claim 4, wherein the wood in the blocks has been dried under constraint to bring about the reduction in its capacity to expand with increase of moisture content.

l0. A flexible wood `floor tile consisting of several parallel rows of several blocks each, bonded to a thick moisture-resistant fibrous membrane, the wood grain in the blocks being parallel to said membrane and running aaeaoae lengthwise of the rows, the blocks in each row being spaced apart end to end so that they are in exactly the same position relative to each other that the wood in the blocks occupied in the living tree, the several rows being spaced apart, the gaps between the block ends being arranged in parallel lines, the width of the gaps, while the wood is comparatively dry between the rows being greater than 2% and less than 6% of the block width, and the moisture-resistant membrane having a thickness of about .02" to .06" and being plastic so that it does not fail in shear when the tile is bonded to a non-expanding base and the blocks expand to the point where the gaps between the rows are closed.

References Cited in the le of this patent UNITED STATES PATENTS 382,852 Apoll May 15, 1888 1,578,020 Elmendorf Mar. 23, 1926 1,825,877 Loetscher Oct. 6, 1931 2,045,382 Elmendorf June 23, 1936 2,118,841 Elmendorf May 31, 1938 2,661,511 Weyerhaeuser Dec. 8, 1953 

